Integrated circuits may be formed on a semiconductor substrate such as a silicon wafer or other semiconductive material. In general, layers of various materials which are semiconductive, conductive, or electrically insulative are used to form the integrated circuits. By way of examples, the various materials may be doped, ion implanted, deposited, etched, grown, etc. using various processes. A continuing goal in semiconductor processing is to strive to reduce the size of individual circuitry components, thereby enabling smaller and denser integrated circuitry. One type of component used in integrated circuitry is a transistor.
Memory is one type of integrated circuitry, and is used in computer systems for storing data. Memory may be fabricated in one or more arrays of individual memory cells. Memory cells may be written to or read from using digit lines (which may also be referred to as bit lines, data lines, sense lines, or data/sense lines) and access lines (which may also be referred to as gate lines or word lines). The digit lines may electrically interconnect memory cells along columns of the array, and the access lines may electrically interconnect memory cells along rows of the array. Each memory cell may be uniquely addressed through the combination of a digit line and an access line.
Memory cells may be volatile, semi-volatile, or non-volatile. Non-volatile memory cells can store data for extended periods of time, in many instances including when the computer is turned off. Volatile memory dissipates and therefore requires being refreshed/rewritten, in many instances multiple times per second. Regardless, memory cells are configured to retain or store memory in at least two different selectable states. In a binary system, the states are considered as either a “0” or a “1”. In other systems, at least some individual memory cells may be configured to store more than two levels or states of information.